Saturday, 27 December 2014

In preparation for some work I will be doing I've been working on calculation of insolation as a function of time and latitude. In this post I will explain the method and compare results to a readily obtainable plot of insolation at various latitudes.

Note, all of the following calculations and the comparison with another source are for top of atmosphere and do not take into account absorption/scattering by the atmosphere, or reflection from clouds.

Sunday, 21 December 2014

The decline in sea ice volume can reasonably be viewed as a process of net energy gain in the Arctic Ocean's ice/ocean system. How can it be possible for the rate of volume loss to reduce, against the trend of past energy gain?

Wednesday, 3 December 2014

The BBC are reporting that this year looks set to be the warmest year across the globe and here in the UK. Although I mainly concentrate on the Arctic and sea ice, I couldn't do that without being all too aware of anthropogenic global warming, so here goes...

Sunday, 30 November 2014

Statistical extrapolation of volume loss has been used to make the claim that the Arctic sea ice faces a rapid decline to a state of summer open water within a few years, or at least this decade. Is this technique likely to give expectations that will be disappointed?

Wednesday, 8 October 2014

The story of the 2014 melt season has been one of unexpected ice survival due to weather being largely unfavourable for largescale ice melt. Now, after a delay to NCEP/NCAR reanalysis data, the PIOMAS volume data is out and it is possible to see how much volume gain will be carried over into the 2014/15 winter, and very likely beyond.

Monday, 15 September 2014

In my July Status blog post I rounded up by mentioning a possible oscillation in August NSIDC Extent losses. Using the Wipneus extent calculation based on NSIDC concentration, and with the benefit of 2014's August figures, I think it is worth looking at the again.

However I don't have a convincing explanation, and at this stage I am not convinced it needs one.

Sunday, 7 September 2014

PIOMAS August data is now out, this is the last monthly status post for 2014. More analysis of this highly unusual year will follow, and occasional commentary on the coming freeze season will follow. But now that the melt season is essentially over there are other sea ice related matter I want to get onto.

Thursday, 4 September 2014

I'm too busy to do a proper write up on the August PIOMAS data, that will remain the case until Sunday. So until then here's one graphic from the August PIOMAS gridded data, I think it puts the significance of 2014 into its proper perspective.

That is a massive slug of thicker ice going into the 2014/15 winter. The derived data has been updated, link, but the daily data has not been updated as gridded hasn't, that doesn't come each month.

Monday, 1 September 2014

I've decided not to await the actual minimum for 2014 to do a post on the season. Now that virtually all the data is in and I've had an afternoon off to do the bulk of the work, here is my 2014 season summary.

Monday, 25 August 2014

I've previously blogged about the anomaly cliff in CT Area during June and its relationship with melt ponding. This anomaly drop is also seen in Wipneus's area and extent calculations based on gridded NSIDC data, it is not peculiar to Cryosphere Today Area.

However are the recent June anomaly cliffs simply due to spread of melt ponding, or is there something else going on?

Tuesday, 5 August 2014

PIOMAS data is now out and the picture of another year of muted melt is confirmed. As of this June the net volume impact of the 2010 volume loss event has been wiped out. However this does not equate to a recovery of thickness or volume across the Arctic. Those still holding out for a crash this year are flogging a dead horse, those expecting a crash by around 2016 are walking towards the same horse, whip in hand.

The regional PIOMAS Data and Thickness Plots that I produce are now updated. See the top right panel on the blog for links.

Wednesday, 23 July 2014

I've been busy with the day job, which has given me time to ponder something I've hinted at before but am now firmly behind. This year isn't a major factor, due to my increased workload in the day job I've had time away from this subject doing something else (often repetitive and boring admin) that has let my subconscious work on the issue - the issue being the long term outlook for Arctic sea ice. Here is what I am now 90% convinced of, having entertained the scenario as a possibility over the last year or so.

Sunday, 20 July 2014

As discussed previously, on 18 June 2014 the weather shifted, the early June delayed start to the melt season came to an end and the melt season started in earnest. Now data is available for 18 July 2014, so I'm giving a brief summary of the sea ice situation one month on.

Tuesday, 15 July 2014

I've had this blog post written but on hold for some months, I never seemed to have the mind to publish, but I've just stumbled upon someone claiming 'no global warming for 18 years', and it's moved me to post.

Sunday, 13 July 2014

This post is really a very late June Status Part 3 because my day job is crowding out this hobby, but rather than restrict to June PIOMAS data, I've added in some extent data to drag it into mid July. So, I'm sorry but that means it's dauntingly long, although I tried to keep the words to a minimum and let the graphs convey message.

Monday, 7 July 2014

This is a rewrite and re-issue of the blog post entitled June PIOMAS data, 2014 prediction revised upward.

Due to increased workload in my day job I've been working late while tired, and in rushing to make the July Sea Ice Prediction Network submission date, I made an error in the spreadsheet. So my 4.7M to 5.1M km^2 prediction was wrong. By now I've missed the deadline and this morning emailed SIPN to ask that my submission be withdrawn as I wouldn't have the chance to re-write it.

The data I provide derived from PIOMAS gridded data has now been updated for June. Daily gridded data has not been updated this month, so the daily regional volume file is not updated. Data are available from this blog post, which also explains the data.

For those who have already read the original post, scroll down to the heading Correction.

This is filler post before we get the PIOMAS data. Wipneus has calculated regional breakdowns of NSIDC extent based on their gridded data, something I started doing but couldn't work out the correct ocean masking to use. Anyway that issue has been solved, Wipneus has been doing the number crunching and has let me have the data.

Thursday, 3 July 2014

Crucial to what I think will happen later this season is the PIOMAS data, as I wait for that the NCEP/NCAR data is now updated, and of course we have extent and area data. So here's the situation over June.

Tuesday, 1 July 2014

Back on the 11 June this year I drew attention to a large polnya in the Laptev Sea and suggested it was likely to play a large role in the 2014 melt season. With data available through to 30 June it's time to see how it's going.

Since posting my rather high prediction on CT Area I've been having doubts about it. A reason to to have confidence in it is the success last year, against the expectations of many including myself. However this year I think CT Area will be at the lower end of the prediction (3.0 to 3.3M km^2), if it is successful, and there is too much of a chance of 2014 being below 3.0 for me to have much confidence in it. The method trains the range to the 2007 to 2013 period, so it is likely overfitted and does not reflect the full range of feasible behaviours after the volume loss events of 2007 and 2010.

Thursday, 26 June 2014

The melt season has started off too late, there will be no CT Area anomaly cliff, and I don't believe that 2012's record will be neared or beaten. However I am making my prediction for CT Area in 2014. CT Area is Cryosphere Today Area, the data is available here.

NOTE - the final part of this blog post has been changed as an error was found in my transformation from CT Area to NSIDC Extent.

Friday, 20 June 2014

Well, it's the 20th of June and CT Area (Cryopsphere Today Area) data for that date is what I've used to make a successful prediction last year. I've also put in a prediction for 2014 September average NSIDC Extent with the Sea Ice Prediction Network, and their June Outlook is now published. Given the weather so far in June, is my SIPN prediction already destined for failure, and what of my June 20th CT Area prediction for 2014?

Wednesday, 4 June 2014

I'm doing this month's PIOMAS data in two posts mainly because work (day job) pressures mean I'm far too tired to do a full post and will be for the rest of the week. I'll catch up over the weekend, that means Sunday, Saturday looks like a day of dozing and watching films. However the notable increase in traffic from Neven's blog suggested to me that I had to do something tonight, so here it is.

Tuesday, 3 June 2014

Changes in Arctic sea ice are a warning to us, and in my opinion one of the best ways to see the warning is through anomalies.

Anomalies are the difference from a long term average, as usual I use the period 1980 to 1999 (20 years) for my long term average. I work out the average value of the index used for each of the 365 days in a standard year and then deduct this value from each daily value of the series 1979 to the present. This transforms the data from a large sinusoidal wave into the differences from that average sinusoidal seasonal cycle, these differences are called anomalies.

I've previously blogged on this for Cryosphere Today Area (CT Area), but thought it worth updating the graphs, this time including NSIDC Extent.

Tuesday, 13 May 2014

New PIOMAS Gridded data is out. My derived regional breakdown data is now updated and a problem with extraneous lines at the end of the thickness/volume breakdowns CSV is now sorted out. I've also tried to semi-automate producing graphs, but as you'll see, this has resulted in a preposterously large title font - not fixed that yet! As I've said previously I consider PIOMAS to be the best long term proxy for sea ice volume and thickness distribution, e.g. here , and here.

Thursday, 8 May 2014

If PIOMAS Gridded data is published I will be posting thickness distributions based on grid box effective thickness, and any other resulting comments. However as the main series PIOMAS data is now out it's worth going over some points I want to raise. It's also worth reading Neven's summary of the past winter, and the May PIOMAS update.

Saturday, 26 April 2014

In my previous post I discussed the results of model forecasts for Arctic sea ice, and have outlined why I am not convinced by GCM results suggesting long term survival of perennial ice well into this century. What happens if the current trend of sea ice losses continues and will the trend of volume loss continue?

Sunday, 20 April 2014

Recently I blogged about a paper showing the cause of the post 1995 volume decline in PIOMAS, this being the period of greatest and most persistent volume loss. The cause turned out to be self-acceleration of volume loss caused by the ice albedo feedback, as this is such a fundamental process and as the later version of the PIOMAS has proven to be so successful, I am in little doubt that Lindsay & Zhang's hypothesis is correct and that in the 1990s atmospheric impacts on the ice ushered in a period of decline largely driven by the ice albedo feedback.

There is really only one issue I can move on to address now, and that is the future of the sea ice.

Tuesday, 8 April 2014

PIOMAS volume data is now out for March. The PIOMAS model uses NCEP/NCAR reanalysis data to drive the ice and ocean components of the model, so the monthly data is for the month up to the final day of the month. Some thickening is due to occur over April in the Arctic Ocean, but this is typically small. So this data can be taken as indicative of conditions as the melt season starts.

Saturday, 5 April 2014

Last year weather led to a pulse of increased volume being fed into the sea ice system, since then we have seen this pulse being severely reduced. Now much of the increased extent of older ice (multi-year ice or MYI) in the Central Arctic has been transported out into Beaufort and is currently making its way into Chukchi. What does this mean for the coming melt season?

Sunday, 23 March 2014

Behind all of my blogging on sea ice is the volume loss, which is driving the changes. The volume loss is shown by other data (e.g. Submarine upward looking sonar, ICESat, IceBridge, Cryosat 2), but the most detailed picture is that provided by PIOMAS. What is driving the volume loss in PIOMAS and is this process at work in reality?

Saturday, 15 March 2014

PIOMAS gridded data has been released for February giving some more detail about current ice state. The peak volume for the whole Arctic is in April, thickening continues in the central Arctic into May, so there is still time for thickening but I don't expect the volume to reach the high level compared to last year. The 2013 volume pulse seems to be largely spent.

Tuesday, 25 February 2014

I've been digging a bit more into record UK rainfall, not a major revelation, but I thought it worth blogging as this blog is essentially my on-line notebook. I don't intend to blog on summer rainfall in the UK again until I've seen what this summer brings.

Thursday, 20 February 2014

The Met Office have today announced that the winter of 2013/2014 (Dec 2013 to February 2014) is the wettest for the UK since records began (1910). Yet, it's still a week to go before the end of the month, and after a week of relatively settled weather, an unsettled week is forecast to take us into the end of the month.

Sunday, 9 February 2014

The UK is experiencing an exceptionally stormy winter, and Met Office chief scientist Dame Julia Slingo has stated "all the evidence suggests there is a link to climate change." Source. The Met Office have produced a detailed account of their findings with regards the exceptional winter of 2013/14, it's available here.

Saturday, 8 February 2014

PIOMAS V2.1 has been released, a partial change to the PIOMAS volume data on the previous version, V2.0. The impact of this change is minimal, and only affects recent years (since 2009). It removes a disparity between my gridded calculations and the Main Series monthly and daily timeseries that are released on the PIOMAS site.

Wednesday, 5 February 2014

Dr Zhang and the team at the Polar Science Centre have been good enough to release PIOMAS gridded data for January, I'm too busy to write much but have just produced a set of graphs illustrating current ice state as modelled in the PIOMAS model. I take the results of that model as a pretty good proxy for the actual ice state. I'll update my datasets over the weekend.

PIOMAS V2.1 has been released by the Polar Science Centre due to a software bug. I'm leaving this post as it stands, some of the graphs shown here are updated to V2.1 in the following post, which is an examination of V2.1. Note that all graphs that follow using January data are already using V2.1, only graphs and numbers referring to 2013 cross reference V2.1 and V2.0, but none of the conclusions are affected.

Monday, 3 February 2014

In the PIOMAS data there has been a change in the seasonal cycle post 2010, which can be noted as a 'spikiness' in recent years of the Polar Science Group's own PIOMAS anomaly plot, see here. This is an anomaly that needs explaining.

Monday, 20 January 2014

The issue of what is causing the increased melt season sea ice losses post 2007 is intriguing, there seems to be two candidate players, the ice and the atmosphere. In my opinion 2013's muted melt gives a hint as to what the main player is.

Sunday, 12 January 2014

An extremely useful tool for winter sea ice watching is ASCAT, the advanced scatterometer. I think it's worth looking at some years of ASCAT for the same day as this is instructive concerning current sea ice state.

Thursday, 9 January 2014

Last February I posted about a break up of sea ice that occurred in the Beaufort Sea, now another break up has happened over the last week. It demands a post, but one looking at the bigger picture, indeed were I to try to go over what has happened in the last week the result would read surprisingly similar to my post of February 2013.

I'm still not totally convinced this is unusual, but there is reason from the scientific literature to expect more sea ice break ups in the Beaufort Sea.

Wednesday, 8 January 2014

Now that PIOMAS data is out and a New Year has begun, it's worth going over some of the data regards sea ice, what I had intended to be my first post before the atmosphere going bonkers derailed my train of thought.

Monday, 6 January 2014

For my first post of the new year I can only start looking at the atmosphere, despite PIOMAS gridded data being out. I have to start here because the atmosphere is going nuts. Here in the UK we've been hammered by a succession of storms from an Atlantic synoptic pattern that keeps defaulting to basin wide monster low pressures. Now over in the States there's a monster of an Arctic Breakout.